/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.skatiger.jrove.el;

import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import javax.el.FunctionMapper;

import org.skatiger.jrove.util.ClassUtil;

public final class FunctionMapperImpl extends FunctionMapper
        implements Externalizable {

    private static class Function
            implements Externalizable {

        protected transient Method m;

        protected String owner;

        protected String name;

        protected String[] types;

        protected String prefix;

        protected String localName;

        public Function() {
            // for serialization
        }

        /**
         * 
         */
        public Function(String prefix, String localName, Method m) {
            this();
            if (localName == null) {
                throw new NullPointerException("LocalName cannot be null");
            }
            if (m == null) {
                throw new NullPointerException("Method cannot be null");
            }
            this.prefix = prefix;
            this.localName = localName;
            this.m = m;
        }

        /*
         * (non-Javadoc)
         * 
         * @see java.lang.Object#equals(java.lang.Object)
         */
        @Override
        public boolean equals(Object obj) {
            if (obj instanceof Function) {
                return this.hashCode() == obj.hashCode();
            }
            return false;
        }

        public Method getMethod() {
            if (this.m == null) {
                try {
                    Class<?> t = ClassUtil.forName(this.owner);
                    Class<?>[] p = ClassUtil.toTypeArray(this.types);
                    this.m = t.getMethod(this.name, p);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            return this.m;
        }

        /*
         * (non-Javadoc)
         * 
         * @see java.lang.Object#hashCode()
         */
        @Override
        public int hashCode() {
            return (this.prefix + this.localName).hashCode();
        }

        @SuppressWarnings("unused")
        public boolean matches(String prefix, String localName) {
            if (this.prefix != null) {
                if (prefix == null) {
                    return false;
                }
                if (!this.prefix.equals(prefix)) {
                    return false;
                }
            }
            return this.localName.equals(localName);
        }

        /*
         * (non-Javadoc)
         * 
         * @see java.io.Externalizable#readExternal(java.io.ObjectInput)
         */
        public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {

            this.prefix = in.readUTF();
            if ("".equals(this.prefix)) {
                this.prefix = null;
            }
            this.localName = in.readUTF();
            this.owner = in.readUTF();
            this.name = in.readUTF();
            this.types = (String[]) in.readObject();
        }

        @Override
        public String toString() {
            StringBuffer sb = new StringBuffer(32);
            sb.append("Function[");
            if (this.prefix != null) {
                sb.append(this.prefix).append(':');
            }
            sb.append(this.name).append("] ");
            sb.append(this.m);
            return sb.toString();
        }

        /*
         * (non-Javadoc)
         * 
         * @see java.io.Externalizable#writeExternal(java.io.ObjectOutput)
         */
        public void writeExternal(ObjectOutput out) throws IOException {
            out.writeUTF((this.prefix != null) ? this.prefix : "");
            out.writeUTF(this.localName);
            out.writeUTF(this.m.getDeclaringClass().getName());
            out.writeUTF(this.m.getName());
            out.writeObject(ClassUtil.toTypeNameArray(this.m.getParameterTypes()));
        }
    }

    private Map<String, Function> functions = null;

    public void addFunction(String prefix, String localName, Method m) {
        if (this.functions == null) {
            this.functions = new HashMap<String, Function>();
        }
        Function f = new Function(prefix, localName, m);
        synchronized (this) {
            this.functions.put(prefix + ":" + localName, f);
        }
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.io.Externalizable#readExternal(java.io.ObjectInput)
     */
    @SuppressWarnings("unchecked")
    public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
        this.functions = (Map<String, Function>) in.readObject();
    }

    @Override
    public Method resolveFunction(String prefix, String localName) {
        if (this.functions != null) {
            Function f = (Function) this.functions.get(prefix + ":" + localName);
            return f.getMethod();
        }
        return null;
    }

    @Override
    public String toString() {
        StringBuffer sb = new StringBuffer(128);
        sb.append("FunctionMapper[\n");
        for (Iterator<Function> itr = this.functions.values().iterator(); itr.hasNext();) {
            sb.append(itr.next()).append('\n');
        }
        sb.append(']');
        return sb.toString();
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.io.Externalizable#writeExternal(java.io.ObjectOutput)
     */
    public void writeExternal(ObjectOutput out) throws IOException {
        out.writeObject(this.functions);
    }
}
